NOS2 and Insulin resistance: Further analyses showed that compared with the SHAM + MSC group, the SPX + MSC group displayed significantly larger adipocytes, lower p-AKT expression,lower Arg-1 expression, less Fizz1-positive cells, and an ascending trend in iNOS-positive cells in EAT, implying that splenectomy impaired the effectiveness of UC-MSCs in alleviating insulin resistance and polarizing macrophages in EAT (Fig. 6H–M).